1. Field of the Invention
The present invention relates to a vehicle steering apparatus and a method for manufacturing the same.
2. Description of the Related Art
A steering apparatus that operates the direction of a vehicle is configured to adjust a tilt position and a telescopic position so as to fit with the physique of a driver. Adjustment of the tilt position is related to the angle of a steering shaft and is recognized as adjustment of the height of a steering wheel for a driver. Adjustment of the telescopic position is related to the length of the steering shaft and is recognized as adjustment of the distance to the steering wheel for a driver.
A general steering apparatus is disclosed in Japanese Patent Application Publication No. 2001-347953. A lower side (the front wheel side) of a steering apparatus is rotatably supported by a lower bracket of a vehicle body and an upper side (the steering wheel side) is fixed by being suspended on a bracket. The steering apparatus has an outer column that grasps a shaft that transmits the rotation of the steering wheel, and the outer column is fixed by being suspended on the bracket.
Adjustment of the telescopic position is performed such that the steering wheel is manually moved back and forth whereby a shaft and an inner column are slid back and forth in the outer column. The steering wheel is clamped and fixed at a desired position by an operating lever (a clamping lever). When the operating lever is operated, the clamping bolt is fastened, the width between the bracket and the outer column narrows, and the shaft and the inner column are fixed.
A cross-section of the outer column has a ring shape having a notch formed in a portion thereof. When the clamping bolt is loosened and fastened, the cross-sectional shape changes slightly and the shaft and the inner column are allowed to slide and are fixed relative to each other.
The outer column, the shaft, and the inner column need to slide smoothly when the operating lever (the clamping lever) is unclamped to adjust the telescopic position. It is very important to machine precisely the inner circumferential surface of the outer column to allow smooth sliding.